The present invention relates to a stopper structure for a seat lifter for adjusting the seat height.
Typically, the seat lifter comprises a pinion gear, a sector gear meshed therewith, and a link swingably provided to the sector gear, wherein the sector gear is rotated in response to input out of the pinion gear to cause swinging of the link, thus adjusting the seat height.
When the pinion gear includes a shaft fixing portion integrated with a base forming member, and the sector gear includes a rotation shaft integrated therewith, for example, assembling is carried out such that the rotation shaft of the sector gear is mounted to the base forming member with the sector gear not meshed with the pinion gear, then, the sector gear is rotated to mesh with the pinion gear.
With the sector gear mounted to the pinion gear in such a manner, however, the sector gear needs an additional part such as a stopper pin or additional machining after assembling so as to prevent disengagement of the sector gear from the pinion gear.
It is, therefore, an object of the present invention to provide a stopper structure for a seat lifter, which can prevent disengagement of the sector gear from the pinion gear with enhanced assembling efficiency and reduced manufacturing cost.
The present invention provides generally a stopper structure for a seat lifter, which comprises: a base frame; a bell crank rotatably mounted to the base frame; a cushion frame linked with one swinging end of the bell crank; a pinion gear rotatably mounted to one of the base frame and the cushion frame; a connecting shaft rotatably mounted to the one of the base frame and the cushion frame; a sector gear meshed with the pinion gear, the sector gear being fixed to the connecting shaft, the sector gear being rotated to swing the bell crank for upward and downward movement of the cushion frame with respect to the base frame; a connecting rod having one end linked with another swinging end of the bell crank and another end linked with the sector gear in a position offset with respect to the connecting shaft; and a stopper formed at the another end of the connecting rod, the stopper abutting on the connecting shaft when the cushion frame is located in at least one of a lifting limit position and a lowering limit position with respect to the base frame, when the cushion frame is located in the lifting limit position the stopper restricting rotation of the sector gear in a direction of lifting the cushion frame with respect to the base frame, when the cushion frame is located in the lowering limit position the stopper restricting rotation of the sector gear in a direction of lowering the cushion frame with respect to the base frame.